Soybeans have long been a staple of the Asian diet in multiple food forms including tofu and soymilk, among many other soy based and fermented foods. Soybeans are excellent sources of protein. Enzyme active soy protein, i.e., soy protein which has not been denatured, has a desirable amino acid profile for nutritional purposes, and includes other health promoting elements such as phytoestrogens. In recent years, demand for soy foods has grown dramatically in the United States and other western countries, principally in the form of meat analogues, nutrition bars and powdered nutrition beverages prepared from soy protein isolates and concentrates. Chemically fractionated soy ingredients and soymilk are prepared by modernized methods to reduce much of the traditional “beany” flavor favored in the East, but severely objected to in the West. Demand for natural and organic foods has grown at an extraordinary rate. Foods designated “natural” and/or “organic” generally cannot utilize chemically processed materials. The soy ingredients commonly used today are not full fat or oil, having been treated with solvents such as hexane to remove fats or oils. The terms “fats” and “oils” are used interchangeably with respect to soybeans in the prior art and in this application. The defatted concentrates or isolates do not qualify as natural or organic, as has been increasingly popular in today's market. U.S. Pat. Nos. 6,495,140 and 6,426,111, for example, illustrate preparation of soy fractionates and/or isolates using solvent extraction.
The soybean flakes useful in making the toasted soybean flakes of the present invention are made from full fat, enzyme active, dehulled soybeans, such as by the method recited in U.S. Pat. No. 4,895,730. This patent is incorporated herein by reference, and is assigned to MicroSoy Corporation, 300 East MicroSoy Drive, Jefferson, Iowa 50129. The soybean flakes used in the present invention qualify as “natural”; and when prepared from soybeans qualifying as organically grown, also qualify as organic foodstuffs.
Full fat, enzyme active (i.e., wherein the proteins are not denatured), dehulled soybeans are excellent sources of elements necessary for good health, and supply outstanding nutritional and nutraceutical benefits. Undenatured soybeans and soybean flakes are excellent sources of protein, iron, vitamin-B, calcium, lecithin and isoflavones. In particular, the lecithin content is from about 2.7 to 3.1 percent. Soybeans also contain essential minerals including phosphorus, which is an essential element used by the body for building bones. Soy isoflavones are now considered helpful in reducing risks for cancer, heart disease, and osteoporosis. Pure soya contains about 38–42% protein, 18–22% fat or oil (of this lecithin is 2.7–3.1%), 25–35% carbohydrate, 1.5–2.5% minerals, 3–5% fiber, and 5–6% water. Full soya flour furnishes about 89 grams of protein per 1000 calories, i.e., about 132 grams of protein and 44 grams oil per 1000 grams. By contrast potatoes contain only about 21 grams of protein per 1,000 calories. In addition, since soybeans do not contain particular glutens, products containing substantial amounts of soybeans offer an alternative for people suffering from celiac disease and/or gluten allergies. Full soya flour contains about three times the grams of protein per 1000 grams as lean beef. A “typical analysis of soy flour and soy grits appears in “The Soybean Digest”, Vol. 19, No. 8, June 1959, pages 8 to 9, as follows:
FullHighLowfatfatfatDefattedProtein, %40.045.048.052.0Fat, %20.015.05.00.5Fiber, %2.52.53.03.0Ash, %5.05.05.56.5Moisture, %8.08.08.08.0MicroSoyR full fat, enzyme active soybean flakes contain 40–48% protein, 19.0% fat/oil, 2.1% fiber, 4.79% ash, 8.08% moisture, and 27.59% carbohydrate.
There exists in the prior art need for soybean and soy protein enriched products, having good taste, texture, and processibility in standard food processing equipment. The present inventors and the prior art faced the problem that unfortunately products containing large amounts of soybeans tend to exhibit undesirable taste and/or texture properties. For example, products containing large amounts of soy materials, may exhibit unpleasant characteristics including chalkiness and/or mouth dryness, grittiness, grassy flavor, bitter flavor, salty flavor, and astringency. The present inventors also faced the problem that amounts of soybean flakes which could be used in various compositions was limited by beany and other objectionable flavors incurred at higher soybean flake concentrations; thus, requiring at higher concentrations the use of expensive triple null variety soybeans. This was especially true of soybean flakes-potato flakes compositions, such as disclosed in copending U.S. patent application Ser. No. 10/382,697, where the amount of soybean flakes was limited to 45%, by the occurrence of beany flavors at higher amounts. This patent application was filed Mar. 6, 2003 in the names of inventors Itaru Tanaka, Safir Moizuddin, and Bruce Liu; and titled COMPOSITION CONTAIING SOYBEAN FLAKES AND POTATO FLAKES, METHOD FOR MAKING A FOOD PRODUCT THEREFROM, AND SAID FOOD PRODUCT. This patent application is incorporated herein by reference; and, will be referred to herein by Ser. No. or as “the '697 application” The present inventors faced the problem that null variety soybeans, especially the expensive triple null, were required to avoid beany flavors. There was clearly a need for soybean flakes which could be made with a wide range of soybean varieties without incurring objectionable beany flavors. Moreover, the present inventors and the prior art faced the problem that soybeans do not contain certain proteins, such as prolamines, gliadin or glutenin, nor sufficient starches, that provide elasticity, cohesiveness and binding during processing.
The present inventors have discovered a method of preparing toasted soybean flakes which significantly reduces and/or eliminates the beany or off-flavors associated with soy materials, while minimizing denaturing of soy proteins. The inventive toasted flakes are made by the inventive process from full fat, enzyme active soybean flakes prepared from dehulled soybeans. They have discovered that unexpectedly high amounts of the inventive toasted soybean flakes can be incorporated in soybean flakes-potato flakes compositions disclosed in the '697 application.
U.S. patent application Ser. No. 10/792,955, has been filed on even date with the present invention, in the name of inventors Itaru Tanaka and Safir Moizuddin, and is titled IMPROVED COMPOSITIONS CONTAINING TOASTED SOYBEAN FLAKES AND POTATO FLAKES, METHOD FOR MAKING A FOOD PRODUCT THEREFROM, AND SAID FOOD PRODUCT. That application discloses toasted soybean flakes-potato flakes compositions containing up to 60% toasted soybean flakes, and is incorporated herein by reference. Use of the inventive toasted flakes unexpectedly permits, contrary to the maximum of 45% soybean flakes set forth in the application Ser. No. 10/382,697, inclusion of up to 60% toasted soybean flakes, while retaining excellent flavor and texture. Application Ser. No. 10/382,697 teaches that amounts higher than 45%, even with soybean flakes made from triple null soybean varieties, results in undesirable changes in taste and texture.
Moreover, as discussed in the '697 application, the average serving of potato (one medium potato or about 148 grams) contains only 3 grams of protein. Thus, there is a need for mashed potato products having significantly increased protein content, without negatively affecting the consumer acceptance thereof, and to make the health claim of providing a minimum of 6.25 grams of soy protein per serving. Moreover, potato products, such as mashed potatoes containing 100% potatoes, are known in the art to exhibit a bland starchy taste and pasty feel. This is due in part to the fact that potatoes contain large amounts of starch, but little or no fat or oil. Moreover, potato is in the nightshade family and suspect in certain arthritic maladies. Soybean flakes-potato flakes compositions made possible by the present invention contain significantly reduced amounts of potato than previously thought possible. Toasting of the full fat, enzyme active soybean flakes by the method of the present invention produces a novel toasted soybean flake which can be used in unexpectedly high amounts of up to about 60% soybean flakes in soybean flake-potato flake compositions, while maintaining desirable taste and texture.
Prior Art
Roasting of soy materials to reduce beany or off-flavors has been generally known in the prior art, as illustrated by U.S. Pat. Nos. 5,936,069 and 3,971,856 (see second paragraph of Description). However, the prior art roasting procedures have generally been carried out, not on full fat, enzyme active soybean flakes made from dehulled soybeans, but on defatted or chemically treated or otherwise prepared soy materials. Furthermore, the roasting processes of the prior art have generally been carried out by heating methods other than that of the present invention, and at temperatures and conditions causing significant denaturing of the soy proteins. The present invention differs variously from the prior art in that the starting soybean flakes are not defatted or chemically treated, or steam heated, or made from soybean meal or flour. The reduction of the soybean material in the prior art to meal or flour significantly increases its exposure to oxidation and results in generation of off-flavors and denaturizaton of the soy proteins. In the present invention the full fat, enzyme active soybean flakes are made from dehulled soybeans, such as by the method shown in U.S. Pat. No. 4,895,730, which flakes are subjected quickly to blown fluidizing dry air heat while moving on and/or above a vibrating surface. The process of the present invention has the additional benefits of reducing fines and of permitting use in applications such as granola-type food bars.
U.S. Pat. No. 6,391,374 is illustrative and teaches pretoasting defatted soy flakes to reduce the bittery or beany off-flavors of the soybean due to lipid peroxidation catalyzed by lipoxygenase.
U.S. Pat. No. 3,971,856 illustrates subjecting dehulled, cracked soybeans to water at 180° F. to a maximum of 212° F. to eliminate any toasting of the soybeans.
U.S. Pat. No. 4,810,513 shows making full fat soybeans flakes from raw soybeans with hulls intact, including the step of drying the flakes in a forced air drier by alternating application of superheated air.
U.S. Pat. No. 4,041,187 illustrates heating tenderized soybean cotyledons sufficiently, such as in an air drier at 200° F. for five minutes, to deactivate the lipoxygenase enzymes.
U.S. Pat. No. 3,941,890 illustrates making soy milk including cooking soybeans in a microwave oven for a time sufficient to destroy the trypsin inhibitor and eliminate any unpleasant beany taste, but for a time insufficient to roast the material.
U.S. Pat. No. 4,103,034 illustrates preparing dried flaked textured vegetable protein from defatted or full-fat soybean flour, which has been dried at temperatures which assure partial or substantial deembitterment without scorching. The '034 patent discusses toasting carried out preferably at between 180 and 200° F. for preferably between 1.5 and 2.5 hours, using hot dry air (page 12).
U.S. Pat. No. 5,710,365 teaches heat treating de-oiled (defatted) soybean flakes to denature the protein therein.
U.S. Pat. No. 4,748,038 illustrates subjecting whole or dehulled and split soybeans to live steam or water for a time sufficient to avoid green, painty or raw flavors developing and short enough such that beany or bitter flavors do not develop.
U.S. Pat. No. 4,409,256 shows making soymilk involving comminuting whole soybeans having the hulls on, forming a slurry and simultaneously heating by an infusion of live steam initiating inactivation of trypsin inhibitor and lipoxygenase without fixing or substantially denaturing the soybean protein.
U.S. Pat. No. 4,639,216 showsflame roasting cereal grains including soybeans to destroy toxic enzymes in the raw soybeans which interfere with digestion and growth in animals, and to sterilize the grain.
U.S. Pat. No. 4,923,710 shows roasting deskinned and split soybean halves which have been soaked for swelling and then dewatered.